"13,200%" increase: Maybe? Leaves out key information.
Any increase: Yes. Multiple studies have shown an increase.
According to the study, the vast majority of patients experienced significantly milder symptoms than are typical for the condition.
Even though almost all individuals with cases of myocarditis were hospitalized and clinically monitored, they typically experienced symptomatic recovery after receiving only pain management. In contrast, typical viral cases of myocarditis can have a more variable clinical course. For example, up to 6% of typical viral myocarditis cases in adolescents require a heart transplant or result in mortality.
The study claims that 1066 patients out of 95,532,396 were reported with Myocarditis, which is one patient per 89,617.
According to the American Heart Association, approximately 3 patients per 1000 suffered from Myocarditis after testing positive for Covid.
An international study published in April 2022 found about 3 in every 1,000 patients hospitalized due to a COVID-19 infection developed acute myocarditis.
A 3:1000 chance to develop Myocarditis is 268.8 times more likely than the increased 1:89,617 chance shown by the study from the vaccination.
A study by Harvard in December 2022 found that 35% of the US population had tested positive for Covid-19 at least once (but 50%+ claimed they had had it). At that 35% rate, you're still 94 times more likely to develop Myocarditis from contracting Covid-19 than you are from getting both doses of the vaccine.
Myocarditis is typically experienced shortly after a viral infection. The paper mentions this, but at a cursory glance contains no information whatsoever about whether or not any of the noted patients also tested positive for Covid-19. Considering that this study is targeted at the first roll out of the Vaccine, which was primarily provided to high-risk individuals, this seems like an extremely important detail missing, as Covid-19 itself can cause Myocarditis at a significantly higher rate.
Leaving out the extremely important factor of whether or not the patients listed in the study had recently suffered from a serious viral infection (the leading cause of Myocarditis) leaves the results suspect, at best.